VirA, a coregulator of Ti-specified virulence genes, is phosphorylated in vitro

High-level expression of a chimeric virA gene was obtained by replacing the first 524 codons of virA with the first half of trpE. The encoded fusion protein was isolated and found to exhibit autokinase activity. Therefore, a kinase domain is in the C-terminal portion of VirA, and protein phosphorylation may be an important feature of VirA function.